An event is being fired on actions (Check/Save/Reset) to keep track of updated problems. On coming back to already visited sequence position, while putting sequence contents in container, only those problems that are found outdated, are going to be updated from earlier tracked problems.

[SUST-40]

Before this commit, calling the student_view on a capa problem would
cause it to render an empty placeholder <div>, wait for the
DOMContentLoaded event to be fired, and then make AJAX requests to the
the problem_get handlers to retrieve the HTML it needed to render the
actual problems. This can significantly increase the end user load
times for pages, particularly when there are many problems in a
vertical.

This commit takes a very conservative approach and has the server side
add the rendered HTML into a new data-content attribute on the <div>
enclosing the problem. When Capa's JS initialization runs, it grabs
from that data-content attribute rather than reaching over the network
for an AJAX request.

I had attempted to make it somewhat smarter and push the rendered
problem straight into the document instead of relying on the
data-content attribute. This was faster, and should be our long term
goal. However, it caused odd bugs, particularly around MathJAX
rendering, and I never quite tracked the issue down. I'm still going
forward with these changes because it's significantly better than the
current situation that students have to deal with, and we can make the
JS more performant in a future iteration.

[PERF-261]

Request API access.

ECOM-3940

Compile js strings when we make dummy strings.

Fix broken French i18n in CMS tests

Safe templating changes for CCX.

French ugettext method was being monkey-patched with a "XYZ " prefix in
all tests. This introduces a context manager to guarantee that the
function reverts to its original state after the unit test has ended
(successfuly or not).

Fix paver watch_assets

Upgrade Underscore.string

Update browser support link

paver uninstall_python_packages

Upgrade to Django 1.8.12

FEDX-117

Translate preferred languages in user account settings

Fix links to moved sections of the developer guide

TNL-4236 – Check for video transcripts before using it

The listed languages in the "preferred languages" input dropdown should
be translated in the user language.

- Update to latest version of watchdog.
- inotify doesn't work on nfs share in devstack. Use polling instead.
- Some editors (vim) do not trigger modify events in their default
  configuration. Rebuild assets on all filesystem changes, and debounce
  when changes happen too quickly.

Using edx-ccx-keys from PyPI

Safe Templatize: wiki templates

Badges V2 Feature Branch

ECOM-4016

MA-2250

Removing check from edx notes settings for OAUTH token timeout.